JPH04236287A - Hot melt adhesive composition - Google Patents

Abstract

PURPOSE:To provide a hot melt adhesive stably giving high adhesive strength in a wide temperature range from low temperature to high temperature and having excellent cold resistance and thermal deterioration resistance. CONSTITUTION:A hot melt adhesive composition is characterized by comprising an amorphous polyolefin (100 pts.wt.) and a polyolefin graft-modified with an unsaturated carboxylic acid, etc., (0.05-25 pts.wt.).

Description

Description: FIELD OF THE INVENTION This invention relates to hot melt adhesive compositions. In more detail, we use paper, wood, plastic, stone, plaster, cement, etc., which have great adhesion ability, excellent cold resistance, no coloration, no odor, and little smoke when burned, and also have improved cohesive strength and heat deterioration resistance. This invention relates to a hot melt adhesive composition that can easily bond metals and the like. [0002] Conventionally, low-viscosity hot-melt adhesives based on amorphous polyolefins have been widely used. This amorphous polyolefin does not have polar groups in its molecular structure and has poor adhesion to plastics, metals, etc., so it is usually blended with rosin or petroleum resin, which is called a tackifier, to give it adhesion. Ta. [0003] However, these rosins and petroleum resins do not necessarily have good compatibility with amorphous polyolefins, and may reduce the cohesive force of hot melt adhesives, or When blended in an amount sufficient to impart adhesive properties, there are drawbacks such as deterioration of low-temperature properties and a decrease in softening point. The inventors have completed the present invention as a result of intensive research aimed at solving the drawbacks of the above-mentioned conventional hot melt adhesives and obtaining a high quality hot melt adhesive. That is, the present invention aims to improve adhesive ability, cold resistance, cohesive force, coloring, odor, cohesive force, heat deterioration resistance, etc., which are disadvantages of conventional hot melt adhesives. [Means for Solving the Problems] According to the present invention, (a)
Amorphous polyolefin 100 with a number average molecular weight of 1,000 to 20,000 and a propylene component of 50% by weight or more
and (b) 0.05 to 50 parts by weight of a modified polyolefin having a number average molecular weight of 2,000 to 30,000 graft-modified with an unsaturated carboxylic acid derivative consisting of an unsaturated carboxylic acid or its anhydride or ester. A hot melt adhesive composition is provided. The present invention will be explained in more detail below. The propylene component of component (a) of the present invention is 50% by weight.
The amorphous polyolefin containing the above may be atactic polypropylene produced as a by-product during the production of crystalline polypropylene, or polypropylene containing a specified propylene component from raw materials or co-propylene with other α-olefins. Polymers can be produced and used as desired. In the case of intended production, for example, a titanium-supported catalyst supported on magnesium chloride and triethylaluminum may be polymerized in the presence of hydrogen. From the viewpoint of supply stability and quality stability, it is preferable to use a specified amorphous polyolefin produced for the purpose. Furthermore, the amorphous polyolefin has a number average molecular weight of 1
,000-20,000, preferably 1,500-15
,000. Specifically, polypropylene, propylene/ethylene copolymer, propylene/butene-1 copolymer, ternary copolymer of propylene, butene-1 and ethylene, having a propylene content and molecular weight within the above ranges; Examples include amorphous polyolefins whose main component is propylene, such as copolymers of propylene and hexene-1, octene-1 or 2-methylpentene-1. Among these, the propylene/ethylene copolymer has an ethylene content of 0 to 30% by weight, preferably 1 to 20% by weight.
It is. When the ethylene content is greater than 30% by weight, the adhesive becomes too soft and has too much surface tackiness, making it difficult to use as an adhesive. In addition, for propylene-butene-1 copolymer, the butene content is 0 to 5.
0% by weight, preferably 5-45% by weight. If the butene-1 content is greater than 50% by weight, the softening point will be too low and productivity will decrease. Furthermore, the amorphous polyolefin of the present invention is
It is preferable that the content insoluble in boiling n-heptane, that is, the content insoluble in Soxhlet extraction with boiling n-heptane is 40% by weight or less, preferably 20% by weight or less, and more preferably 15% by weight or less. Furthermore, it is preferable that the amorphous polyolefin of the present invention hardly generates an endothermic peak during crystal melting in temperature rise measurement using a differential scanning calorimeter. In the amorphous polyolefin of the present invention, if the content insoluble in boiling n-heptane is higher than the above range or if the heat of crystal fusion is large, when used as an adhesive, the open time may be too short, or the flesh may become thin after application. This is not preferable because it causes problems such as changes in adhesive strength over time. As the amorphous polyolefin in the present invention, for example, commercially available REXT
AC) etc. can be used. The polyolefin used in the modified polyolefin as component (b) of the present invention may be a propylene or ethylene homopolymer, a copolymer thereof, or a combination thereof with hexene-1, octene-1, 2-methylpentene. -1, a copolymer with acrylic ester, vinyl acetate, etc. is used. Among these, polypropylene is particularly preferred because of its good compatibility. The modified polyolefin of component (b) of the present invention is obtained by graft-modifying the polyolefin with a modifier of an unsaturated carboxylic acid, an unsaturated carboxylic acid derivative (hereinafter referred to as unsaturated carboxylic acid, etc.) consisting of an anhydride or ester thereof. You can get it. Modifiers such as unsaturated carboxylic acids include, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo(2,2
, 1) Unsaturated carboxylic acids such as hept-2-ene-5,6-dicarboxylic acid, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo(2,2,1)hept-2 Anhydrides of unsaturated carboxylic acids such as -ene-5,6-dicarboxylic anhydride, methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, Dimethyl tetrahydrophthalic anhydride, bicyclo(2,2,1)hept-2-
Specific examples include unsaturated carboxylic acid esters such as dimethyl ene-5,6-dicarboxylate. Among these,
Maleic acid, itaconic acid or anhydrides thereof are preferred. Graft modification can be carried out by a known method, for example, by melt-kneading a polyolefin and a modifier such as an unsaturated carboxylic acid together with a peroxide. The modified polyolefin graft-modified with unsaturated carboxylic acid etc. of the present invention has a number average molecular weight of 2,000.
0 to 30,000. Number average molecular weight is 30,000
If it is larger than this, the melt viscosity becomes high and there is a problem in workability, and if it is less than 2,000, the cohesive force is low and sufficient adhesive strength cannot be obtained. In addition, the grafting concentration of the modifying agent is 0.5~
It is 20% by weight. If it is less than 0.5% by weight, adhesive strength and heat deterioration resistance will not improve. If the amount exceeds 20% by weight, the modified polyolefin becomes seriously colored and gives off an odor, causing problems in handling. Further, the modified polyolefin may be crystalline or substantially amorphous. The adhesive composition of the present invention can be obtained by blending the above-mentioned amorphous polyolefin and the above-mentioned modified polyolefin. The blending ratio is 100% amorphous polyolefin
The modified polyolefin is contained in an amount of 0.05 to 25 parts by weight, preferably 0.1 to 20 parts by weight, and if the modified polyolefin is less than 0.05 parts by weight, the effects of the present invention cannot be obtained; Even if it exceeds 25 parts by weight, no further effect can be obtained. In the present invention, tackifiers, resins, oils, waxes, etc. are added to the composition of amorphous polyolefin and modified polypropylene in order to adjust melt viscosity, cohesive force, temperature dependence, etc. can be used. Tackifiers used in the present invention include natural rosin (gum rosin, wood rosin, tall oil rosin, etc.), modified rosin (polymerized rosin, hydrogenated rosin, etc.), coumaron/indene resin, terpene resin, aliphatic, alicyclic rosin, etc. Petroleum resins such as petroleum resins, aromatic resins, phenolic resins, etc. can be used. Further, as resins, ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer, ethylene/ethyl acrylate copolymer, ethylene/methyl acrylate copolymer, styrene/ethylene/butylene/ Styrene block copolymers, ethylene-propylene copolymers or ethylene-butene copolymers with a molecular weight of 30,000 or more, polybutenes, waxes, and polymers and copolymers modified with these acids, metal salts of acids, halogens, etc. You can use combinations etc. These tackifiers and resins can be used alone or in combination of two or more. Alternatively, liquid oil can also be used. Furthermore, conventionally known additives such as various fillers, antioxidants, etc. may be added as compounds other than those mentioned above. As the filler, clay, talc, calcium carbonate, barium carbonate, etc. can be used, and organic and inorganic fibrous reinforcing materials can also be used. Antioxidants include dilauryl thiodipropionate, pentaerythrityl-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5
-di-t-butyl-4-hydroxyphenyl)propionate, tris(2,4-di-t-butylphenyl)phosphite, 2,6-di-tert-butyl-4-
Methylphenol, phenyl-α-naphthylamine, etc. can be used. [0014] In the present invention, an amorphous polyolefin,
To blend the modified polyolefin, filler, etc., these components may be mixed and heated in a container, or rolls, Banbury mixers, kneaders, extruders, etc., which are commonly used for mixing polymers, may be used. Since the adhesive of the present invention melts when heated, it can be molded into various shapes such as blocks, pellets, strings, and films. The adhesive of the present invention can be applied by melting the adhesive onto the adherends using an ordinary hot melt adhesive applicator and bonding the adherends together, or by applying the adhesive to one of the adherends in advance. , a method in which the other adherend is overlapped and heated, a method in which a film-like adhesive is bonded together using a laminator, etc. are used. Adherents to which the adhesive of the present invention can be used include paper, cloth, wood, synthetic resins such as polyethylene, polypropylene, polyvinyl chloride, plaster, cement, stone, metallic glass, etc. can be mentioned. In addition, moisture-proof/waterproof paper with a sandwich-like structure made of paper and/or paperboard bonded together with hot-melt adhesive, and moisture-proof/waterproof paper with hot-melt adhesive coated on one side of paper and/or paperboard. Can be used. Furthermore, it can also be used as an adherend to fill gaps between objects of the same type or different types as described above, that is, as a sealant. [Example] The present invention will be explained in detail below with reference to Examples. However, the present invention is not limited to the following examples. Example 1 As an amorphous polyolefin, a propylene/butene-1 weight ratio of 65/35 and a number average molecular weight Mn of 6500, manufactured by Rexen Corporation in the United States, was used under the trade name REXTAC RT2.
780 100 parts by weight contains an acid-modified wax as a modified polyolefin with a number average molecular weight Mn of 15,000.
Then, 0.3 parts by weight of modified polypropylene Umex 1001 (manufactured by Sanyo Chemical Industries, Ltd.) having a graft concentration of 5% by weight with maleic anhydride was heated and melted and mixed to prepare a hot melt adhesive. Next, the obtained adhesive was applied to a thickness of 60μ on a polyethylene terephthalate film, and then another polyethylene terephthalate film was layered and pressed for 10 seconds at 120°C and a pressure of 3kg/cm2 to bond the films together. . There was no odor at all during this time. This laminated film was cut into strips with a width of 25 mm, and the peeling speed was 300 mm/min.
Peel strength was measured. The measurement results are shown in Table 1. Example 2 A hot melt adhesive was obtained in the same manner as in Example 1 except that the amount of modified polyolefin was changed to 1 part by weight. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 1. Example 3 A hot melt adhesive was obtained in the same manner as in Example 1 except that the amount of modified polyolefin was changed to 5 parts by weight. The T-peel strength of the obtained adhesive was measured in the same manner as in the examples. The measurement results are shown in Table 1. Example 4 A hot melt adhesive was obtained in the same manner as in Example 1 except that the amount of modified polyolefin was changed to 10 parts by weight. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 1. [Table 1] [0021]
Example 5 In Example 2, the amorphous polyolefin was homopolypropylene manufactured by Lexen Corporation in the United States, and the number average molecular weight Mn
is 7200. Product name REXTAC RT2180
A hot melt adhesive was obtained in the same manner as in Example 2 except that . The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 2. [Table 2] [0023]
Example 6 In Example 2, as the amorphous polyolefin, propylene/ethylene (weight ratio) manufactured by Lexen Corporation of the United States was used at a ratio of 97/
3, and the number average molecular weight Mn is 7200.
A hot melt adhesive was obtained in the same manner as in Example 2 except that XTAC RT2280 was used. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 2. Example 7 In Example 2, the amorphous polyolefin was propylene/ethylene (weight ratio) of 93/
7, and the number average molecular weight Mn is 7400.
The same procedure as in Example 2 was carried out except that XTAC RT2385 was used. The T-peel strength of the obtained adhesive was measured in Example 1.
It was measured in the same way. The measurement results are shown in Table 2. Example 8 In Example 2, the amorphous polyolefin was propylene/ethylene (weight ratio) of 85/
15, and the number average molecular weight Mn is 7100.
A hot melt adhesive was obtained in the same manner as in Example 2 except that EXTAC RT2585 was used. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 2. Comparative Example 1 Hiretz was added as a tackifier to 70 parts by weight of the propylene-butene-1 copolymer (trade name: REXTACRT2780, manufactured by Rexen, USA, used in Example 1 as the amorphous polyolefin) in place of the modified polypropylene Umex 1001. T1115 (manufactured by Mitsui Petrochemical Industries, Ltd.)
A hot melt adhesive was obtained in the same manner as in Example 1, except that 30 parts by weight were heated and melted and mixed. T of the resulting adhesive
Peel strength was measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative Example 2 A hot melt adhesive was obtained in the same manner as in Example 1, except that REXTACRT2780 (trade name, manufactured by Lexen, Inc., USA) was used as the amorphous polyolefin, and modified polypropylene was not used. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative Example 3 A hot melt adhesive was obtained in the same manner as in Example 5, except that the amorphous polyolefin used in Example 5 was REXTACRT2180 (trade name, manufactured by Rexen, Inc., USA) and the modified polypropylene was not used. Ta. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative Example 4 A hot melt adhesive was obtained in the same manner as in Example 6, except that the amorphous polyolefin used in Example 6 was REXTACRT2280 (trade name, manufactured by Rexen, USA) and the modified polypropylene was not used. Ta. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative Example 5 A hot melt adhesive was obtained in the same manner as in Example 7, except that the amorphous polyolefin used in Example 7 was REXTACRT2385 (trade name, manufactured by Rexen, USA) and the modified polypropylene was not used. Ta. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 3. Comparative Example 6 A hot melt adhesive was obtained in the same manner as in Example 8, except that the amorphous polyolefin used in Example 8, trade name REXTACRT2585 manufactured by Rexen, USA, was used, and the modified polypropylene was not used. Ta. The T-peel strength of the obtained adhesive was measured in the same manner as in Example 1. The measurement results are shown in Table 3. [Table 3] From the above Examples and Comparative Examples, the hot melt adhesive made of the amorphous polyolefin and modified polyolefin of the present invention has strong adhesive strength at low temperatures and is excellent in cold resistance. I understand. Effects of the Invention The hot melt adhesive composition of the present invention has the following properties:
High adhesive strength is stably obtained from low temperatures (approximately -20°C) to high temperatures (approximately 60°C), has good cold resistance and heat deterioration resistance, is free from coloration, and produces little smoke when burned. It also has advantages such as no odor.

Claims (3)

[Claims] Claim 1: (a) Number average molecular weight is 1,000 to 2
0,000, 100 parts by weight of an amorphous polyolefin having a propylene component of 50% by weight or more, and (b) an unsaturated carboxylic acid derivative consisting of an unsaturated carboxylic acid or its anhydride or ester, with a number average molecular weight of 2. ，
000~30,000 modified polyolefin 0.05~
50 parts by weight of a hot melt adhesive composition. 2. The amorphous polyolefin contains 70 to 100% by weight of propylene and 0 to 30% by weight of ethylene.
Claim 1 is a propylene-ethylene copolymer containing
The hot melt adhesive composition described. 3. The hot melt adhesive according to claim 1, wherein the amorphous polyolefin is a propylene-butene-1 copolymer containing 50 to 90% by weight of propylene and 10 to 50% by weight of butene-1. Composition.